1. Field of the Invention
This invention relates to an engine control apparatus for performing a gear-shift operation and a throttle operation of an engine of a boat, for example, by way of a single control lever.
2. Description of the Related Art
Engine control apparatuses which are capable of performing a gear-shift operation (shift operation) and a throttle operation of an engine of a boat by way of a single control lever are known. As described in Jpn. Pat. Appln. KOKOKU Publication No. 3-35505 (Patent Document 1), for example, a control apparatus having a shift drive unit and a throttle drive unit accommodated in a single housing is publicly known. In such a control apparatus, a control lever is pivoted by a predetermined amount to a forward position (an ahead position) or a reverse position (an astern position) from the neutral position. Then, via a Geneva gear mechanism interlocked with the control lever, a shift cable is moved to the forward position or the reverse position. When the control lever is further pivoted, the control lever enters into a throttle operation range. In the throttle operation range, as a cam member moves in accordance with the position of the control lever, a throttle cable moves in accordance with a position of a cam follower.
In this type of engine control apparatus, a friction mechanism for producing a certain degree of frictional force to be applied to the control lever is provided for preventing the control lever from inadvertently moving when it is in the throttle operation range. For example, in the control apparatus of Patent Document 1, by pressing a brake shoe against an inner surface of a brake chamber of a housing body, a frictional force is produced and applied to the control lever.
A single lever type control apparatus of Patent Document 1 has a long track record of being used as an engine control apparatus for a boat. However, the throttle drive unit of Patent Document 1 is configured such that an operation of the control lever is transmitted to the throttle cable via the cam member. Accordingly, transmission efficiency of force is sometimes relatively low depending on the relative position of the cam member and the cam follower. In such a case, a large force of operation is required. Also, the conventional engine control apparatus has room for improvement to deal with situations such as a frictional force being suddenly reduced when the brake shoe is worn out.